Filter by Category

SFTP Server in the DMZ or Private Network

Many organizations have an SFTP server installed where their trading partners can connect to securely upload and download sensitive files.

SFTP Server in the DMZ

Traditionally SFTP Servers have been installed in the DMZ (or public facing) segment of the network since organizations were fearful of opening inbound ports into the Private (internal) network.

Process for how a DMZ secure gateway works

Keeping the SFTP Server in the DMZ, however, has posed several problems. The primary issue is that files have to be stored in the DMZ when they are dropped off by partners, or otherwise staged temporarily for pickup. Those staged files have a higher risk of being accessed by hackers since the DMZ is more exposed to the Internet. You could require those staged files to be encrypted with something like Open PGP, but many auditors don't like to see any sensitive files in the DMZ, encrypted or not. Another issue is that you often have to write scripts to copy the files back and forth between the DMZ and private network, which takes programmer effort and can lead to errors.

SFTP Server in the Private Network

To keep sensitive files out of the DMZ, some organizations have moved their SFTP server into the private network.

This approach eliminates the need to write scripts for moving files back and forth. The big downfall of this approach is that ports were traditionally opened into the private network for trading partners to gain access to the SFTP server. These open ports could create a potential risk for attackers to gain access to the private network. In today's security-conscious environment, most IT auditors do not like to see any inbound ports opened into the private network... especially if you are storing sensitive PCI DSS or HIPAA data on those servers.

Gateway in the DMZ while keeping the SFTP Server in the Private Network

An approach that is quickly gaining in popularity is to implement a gateway component in the DMZ. The gateway will serve as an enhanced reverse proxy which does not require inbound ports into the private network.

At startup time, the SFTP server will establish a special control channel with the gateway, which is kept alive continuously. When partners connect to the gateway, it will make requests over the existing control channel to the SFTP server. The SFTP server will then open any data channels needed back through the gateway to service the trading partners. The whole process is transparent to the trading partners. No data is ever stored in the DMZ since it is simply streamed through the gateway.

A gateway in the DMZ therefore solves two major security issues:

  1. No files need to be stored in the DMZ, including user credentials
  2. No inbound ports need to be opened into the Private network

Since a proprietary control channel is used to communicate between the gateway and the SFTP server, you will need to purchase both components from a single vendor. When looking for the right gateway for your organization, make sure it is easy to set up and manage. It is critical that it does not require inbound ports into the private network or require any data to be stored in the DMZ.

Want to learn more about DMZ Secure Gateways? View this informative whitepaper: DMZ Secure Gateways: Secret Weapons for Data Security.

DMZ Secure Gateways: Secret Weapons for Data Security, the white paper

Latest Posts


The Cybersecurity Dangers of the Dark Web and How to Protect Your Organization

September 29, 2020

Even as cybersecurity experts and researchers declare that the “underground golden age is over” as its top marketplaces are raided or close their doors, the dark web continues to thrive. In fact,…


iPaaS and MFT: What You Need to Know

September 24, 2020

Once upon a time, you carried an MP3 player to listen to music, a cell phone to text and make calls, and a book if you wanted to read. Video games and the internet? Best to use your preferred gaming…


What is Electronic File Transfer?

September 22, 2020

Meet Electronic File Transfer If your IT department is still relying on outdated methods like FTP, PC tools, or legacy scripts to meet your organization’s data transfer needs, now is the time to…


What is a Cloud Connector?

September 17, 2020

The cloud and all its possibilities for connecting with customers, vendors, trading partners, and more is exciting. Managing your organization’s transition to the cloud – whether you’re…


How Amazon Web Services Works with GoAnywhere MFT

September 16, 2020

“Alexa, What is MFT?” While that may not be a question you’ve ever asked your virtual assistant, it’s not outside the realm of possibility – Amazon has quickly become ubiquitous for online…